1. Field of the Invention
The present invention relates to an ink, an ink cartridge containing the ink, and an image-recording method using the ink.
2. Description of the Related Art
Hitherto, an ink containing a pigment (hereinafter referred to as “polymer-dispersed pigment”), dispersed with polymer, serving as a colorant has been used in an image-recording method for the purpose of increasing the abrasion resistance of images. However, the ink containing the polymer-dispersed pigment has a problem that the optical density of images is low, although the abrasion resistance of images is relatively high. Therefore, attempts have been made to increase the optical density of images in such a way that the evaporation of water is facilitated by reducing the amount of water in the ink containing the polymer-dispersed pigment and the aggregation of pigment on paper is accelerated as disclosed in Japanese Patent Laid-Open No. 2003-226827 (hereinafter referred to as the patent document). The patent document discloses ink containing the polymer-dispersed pigment and various organic agents such as a humectant and a penetrant.